Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt

   1 * Atmel AT91 Pinmux Controller
   2
   3 The AT91 Pinmux Controller, enables the IC
   4 to share one PAD to several functional blocks. The sharing is done by
   5 multiplexing the PAD input/output signals. For each PAD there are up to
   6 8 muxing options (called periph modes). Since different modules require
   7 different PAD settings (like pull up, keeper, etc) the contoller controls
   8 also the PAD settings parameters.
   9
  10 Please refer to pinctrl-bindings.txt in this directory for details of the
  11 common pinctrl bindings used by client devices, including the meaning of the
  12 phrase "pin configuration node".
  13
  14 Atmel AT91 pin configuration node is a node of a group of pins which can be
  15 used for a specific device or function. This node represents both mux and config
  16 of the pins in that group. The 'pins' selects the function mode(also named pin
  17 mode) this pin can work on and the 'config' configures various pad settings
  18 such as pull-up, multi drive, etc.
  19
  20 Required properties for iomux controller:
  21 - compatible: "atmel,at91rm9200-pinctrl" or "atmel,at91sam9x5-pinctrl"
  22                 or "atmel,sama5d3-pinctrl"
  23 - atmel,mux-mask: array of mask (periph per bank) to describe if a pin can be
  24   configured in this periph mode. All the periph and bank need to be describe.
  25
  26 How to create such array:
  27
  28 Each column will represent the possible peripheral of the pinctrl
  29 Each line will represent a pio bank
  30
  31 Take an example on the 9260
  32 Peripheral: 2 ( A and B)
  33 Bank: 3 (A, B and C)
  34 =>
  35
  36   /*    A         B     */
  37   0xffffffff 0xffc00c3b  /* pioA */
  38   0xffffffff 0x7fff3ccf  /* pioB */
  39   0xffffffff 0x007fffff  /* pioC */
  40
  41 For each peripheral/bank we will descibe in a u32 if a pin can be
  42 configured in it by putting 1 to the pin bit (1 << pin)
  43
  44 Let's take the pioA on peripheral B
  45 From the datasheet Table 10-2.
  46 Peripheral B
  47 PA0     MCDB0
  48 PA1     MCCDB
  49 PA2
  50 PA3     MCDB3
  51 PA4     MCDB2
  52 PA5     MCDB1
  53 PA6
  54 PA7
  55 PA8
  56 PA9
  57 PA10    ETX2
  58 PA11    ETX3
  59 PA12
  60 PA13
  61 PA14
  62 PA15
  63 PA16
  64 PA17
  65 PA18
  66 PA19
  67 PA20
  68 PA21
  69 PA22    ETXER
  70 PA23    ETX2
  71 PA24    ETX3
  72 PA25    ERX2
  73 PA26    ERX3
  74 PA27    ERXCK
  75 PA28    ECRS
  76 PA29    ECOL
  77 PA30    RXD4
  78 PA31    TXD4
  79
  80 => 0xffc00c3b
  81
  82 Required properties for pin configuration node:
  83 - atmel,pins: 4 integers array, represents a group of pins mux and config
  84   setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>.
  85   The PERIPH 0 means gpio, PERIPH 1 is periph A, PERIPH 2 is periph B...
  86   PIN_BANK 0 is pioA, PIN_BANK 1 is pioB...
  87
  88 Bits used for CONFIG:
  89 PULL_UP         (1 << 0): indicate this pin needs a pull up.
  90 MULTIDRIVE      (1 << 1): indicate this pin needs to be configured as multi-drive.
  91                         Multi-drive is equivalent to open-drain type output.
  92 DEGLITCH        (1 << 2): indicate this pin needs deglitch.
  93 PULL_DOWN       (1 << 3): indicate this pin needs a pull down.
  94 DIS_SCHMIT      (1 << 4): indicate this pin needs to the disable schmitt trigger.
  95 DRIVE_STRENGTH (3 << 5): indicate the drive strength of the pin using the
  96                         following values:
  97                                 00 - No change (reset state value kept)
  98                                 01 - Low
  99                                 10 - Medium
 100                                 11 - High
 101 DEBOUNCE        (1 << 16): indicate this pin needs debounce.
 102 DEBOUNCE_VAL    (0x3fff << 17): debounce value.
 103
 104 NOTE:
 105 Some requirements for using atmel,at91rm9200-pinctrl binding:
 106 1. We have pin function node defined under at91 controller node to represent
 107    what pinmux functions this SoC supports.
 108 2. The driver can use the function node's name and pin configuration node's
 109    name describe the pin function and group hierarchy.
 110    For example, Linux at91 pinctrl driver takes the function node's name
 111    as the function name and pin configuration node's name as group name to
 112    create the map table.
 113 3. Each pin configuration node should have a phandle, devices can set pins
 114    configurations by referring to the phandle of that pin configuration node.
 115 4. The gpio controller must be describe in the pinctrl simple-bus.
 116
 117 Examples:
 118
 119 pinctrl@fffff400 {
 120         #address-cells = <1>;
 121         #size-cells = <1>;
 122         ranges;
 123         compatible = "atmel,at91rm9200-pinctrl", "simple-bus";
 124         reg = <0xfffff400 0x600>;
 125
 126         atmel,mux-mask = <
 127               /*    A         B     */
 128                0xffffffff 0xffc00c3b  /* pioA */
 129                0xffffffff 0x7fff3ccf  /* pioB */
 130                0xffffffff 0x007fffff  /* pioC */
 131               >;
 132
 133         /* shared pinctrl settings */
 134         dbgu {
 135                 pinctrl_dbgu: dbgu-0 {
 136                         atmel,pins =
 137                                 <1 14 0x1 0x0   /* PB14 periph A */
 138                                  1 15 0x1 0x1>; /* PB15 periph A with pullup */
 139                 };
 140         };
 141 };
 142
 143 dbgu: serial@fffff200 {
 144         compatible = "atmel,at91sam9260-usart";
 145         reg = <0xfffff200 0x200>;
 146         interrupts = <1 4 7>;
 147         pinctrl-names = "default";
 148         pinctrl-0 = <&pinctrl_dbgu>;
 149         status = "disabled";
 150 };